Methods and apparatus for radio frequency sensing in diverse environments

US11308291B2 · kind B2 · utility

Assignee

• Massachusetts Institute of Technology · US

Inventors

• Unsoo Ha · Cambridge, US
• Junshan Leng · Malden, US
• Alaa Khaddaj · Cambridge, US
• Yunfei Ma · Ithaca, US
• Tzu Ming Hsu · Cambridge, US
• Zexuan Zhong · Princeton, US
• Fadel Adib · Cambridge, US

Key dates

• Filing date: Oct 25, 2020
• Grant date: Apr 19, 2022
• Expiry date: Oct 25, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G06K19/0723
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A system may sense the contents of a closed container, by analyzing a wireless signal that reflects from an RFID tag on the outside of the container. The frequency response of the tag's antenna may be affected by the relative permittivity of the contents and by the tag's environment. The frequency response may be measured in a line-of-sight environment and in a multipath environment. Channel estimates may be calculated, based on the measurements. Channel ratios may be calculated by dividing line-of-sight channel estimates by multipath channel estimates. The resulting channel ratios may be fed into a variational autoencoder, which in turn generates synthetic data that contains information about multipath environments but not the contents. The output of the variational autoencoder may be converted into synthetic channel estimates, which may in turn be employed for anomaly detection, or to train a classifier to classify contents of the container.